JP4827355B2 - Dual-band RF power tube with shared collector and related method - Google Patents

Description

[0001]
FIELD OF THE INVENTION
This invention relates generally to high power radio frequency (RF) amplifiers and related amplification methods used in radar, communications, and other applications, and in particular, the interaction of an RF signal with a modulated electron beam in a vacuum tube. The present invention relates to a tube-type RF output amplifier such as a klystron tube or a traveling wave tube (TWT), in which an RF gain is provided.
[0002]
BACKGROUND OF THE INVENTION
In general, many radar and satellite communications applications require the provision of a frequency (RF) transmitter capable of delivering very high peaks or average levels of RF output, for example, radar pulses in radar applications. It is necessary to generate a high output continuous signal for communication application. Although solid-state approaches to transmitter amplifiers have been developed in recent years and it has become possible to produce ever increasing levels of RF power, many applications at higher RF frequencies where high peak or average power levels are required are Traveling wave tube ("TWT") or klystron tube type amplifiers must be used.
[0003]
A typical TWT or klystron tube is a vacuum tube that includes an electron beam source, such as an anode structure, to which a high voltage is applied at an elevated temperature at one end of the tube. The electron beam generated by the anode travels the entire length of the tube structure and is collected by a collector at the end of the tube opposite the anode. Due to the high flux of electrons through the tube, the collector elements are usually large and bulky. Furthermore, a considerable amount of heat sink is required to dissipate the large amount of heat generated by collecting electrons.
[0004]
In operation, an RF signal is introduced near the end of the anode in the tube. The RF signal interacts with the electron beam in a delay structure within the tube, or “slow wave” structure, and is significantly amplified in the tube. By extracting the RF signal near the end of the tube, a high level peak or continuous RF output can be delivered.
[0005]
Traveling wave tube amplifiers (“TWTA”) generally consist of a TWT and an associated high voltage power supply. Within this tube structure, the TWT typically includes a slow wave structure that surrounds the electron beam and extends longitudinally within the tube. By sending an RF signal along the slow wave structure, the RF signal interacts with the electron beam and is continuously amplified throughout the length of the slow wave structure. A TWT generally also includes a plurality of focusing magnets along the length of the tube and an attenuator to reduce the wave, but without this attenuator, the wave travels backward, i.e., back in the tube. End up.
[0006]
The klystron tube also requires a high voltage power source. In contrast to TWT, klystron tubes typically contain several separate cavities in which the RF signal is amplified. The RF signal is carried between the cavities by the electron beam, but the RF signal is not coupled between the cavities, so the amplification of the RF signal is not continuous over the length of the tube.
[0007]
In addition to the TWTs described above, TWTs with coupled cavities have been designed that essentially include dozens of klystron-like cavities that are electromagnetically coupled together, allowing RF signals to propagate therethrough. For a description of klystron tubes and TWTs, see A. S. See AS Gilmour, Jr., “Microwave Tubes”, Artech House (1986).
[0008]
In many applications where TWT and klystron tubes are deployed, such as satellite communications applications, minimizing the weight and size of the transmitter hardware is often important for a number of reasons. However, as a result of the size and weight of all tube structures including the collector element, TWT and klystron tubes are inherently bulky and heavy, for example when compared to solid alternatives. Thus, the weight and size of the collector in such tube-based transmitters often becomes a significant part of the overall transmitter weight and size. The weight and size of the tube is often an important factor in determining the overall design for a radar system or satellite transmitter. As a result, transmitter system designers have used a number of techniques to minimize weight and size. For example, Daterich A. U.S. Pat. No. 4,232,249 to Dietrich A. Alsberg proposes a TWT structure with a single anode or electron gun element. An electron beam with controllable deflection can be generated and passed through either of two different delay structures, collected by different respective collectors, each of which can be thermally connected to a common collector heat sink.
[0009]
In some radar or communication applications, high RF power levels must be generated at each of two or more different RF frequencies. For example, some communication systems operate at multiple frequencies, while other radar systems improve the performance of radar systems by using multi-frequency transmitters. When the various frequencies of the transmitter are in close proximity to each other in a multi-frequency system, only one TWT or klystron tube can be used to provide RF gain and power at all required frequencies. . However, in some applications, conventional TWTs or klystrons cannot be used because the various frequencies of the transmitter are very widely dispersed in frequency. In such applications, a number of TWTs or klystrons must be used, each of which includes a relatively large and bulky collector element and a high voltage power supply. As a result, the transmitter system is disadvantageously large and heavy, which can limit the usefulness of the transmitter system in weight sensitive applications such as satellite or airborne hardware applications. Let's go.
[0010]
SUMMARY OF THE INVENTION
In accordance with the present invention, an RF transmitter and associated method is provided for generating a plurality of amplified output signals in response to a plurality of RF input signals. The RF transmitter of the present invention includes a plurality of RF tube sections. Each tube defines an input and an output, through which RF signals are respectively introduced and extracted.
[0011]
Each tube typically amplifies RF signals having different frequencies, but can also amplify RF signals of the same frequency. Each RF tube section has an anode and amplifies the RF signal by generating an electron beam passing through the tube section. In accordance with the present invention, the RF transmitter further includes a common collector and collects each electron beam after propagating through each of the RF tubes. In this regard, it is desirable that the common collector be positioned adjacent to the end of each RF tube section opposite the anode end to facilitate collection of each electron beam. By using a common collector for each RF tube, the weight of the RF transmitter is reduced compared to a conventional RF transmitter having multiple tubes with individual collectors and individually amplifying different RF signals. The size is advantageously reduced.
[0012]
In addition to sharing a common collector, the RF transmitter is shared by each RF tube section and can include a modulator for modulating each electron beam. Furthermore, it is preferable that the plurality of RF tube portions define a common vacuum tube such as a klystron tube or a traveling wave tube in cooperation. The RF transmitter may further include a power source for energizing the RF tube section and a heat sink for dissipating heat generated in the common collector as the electron beam is collected.
[0013]
By using a common element, such as a common collector, and in some embodiments a common modulator, the RF transmitter and associated method of the present invention allows multiple RF signals that may have different frequencies. Can be amplified by each of the RF tubes, while the overall weight of the RF transmitter compared to conventional designs having multiple components with individual elements, i.e., individual collectors, The size is reduced. Thus, the RF transmitter and related methods of the present invention are particularly advantageous for applications where cumulative weight and size are to be minimized, such as satellite communications and other airborne or space related applications.
[0014]
[Detailed explanation]
The present invention will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. All the same numbers refer to the same elements.
[0015]
In accordance with an embodiment of the present invention, an RF transmitter 20 such as a radar transmitter or communication amplifier is shown in FIG. The RF transmitter includes a tube housing 22 that is typically formed from light metal. The RF transmitter further includes a TWT tube, a klystron tube, or other suitable high power vacuum tube disposed within the tube housing for amplifying the RF signal. In addition, the RF transmitter has a collector and a beam voltage source and a bias voltage source, as will be described in further detail below in conjunction with FIG. In the RF transmitter, and in some embodiments, the power supply further includes a heater source and an electron beam modulator, as described below in conjunction with FIG. In accordance with the present invention, as shown in FIG. 1, within a two-band RF transmitter 20, the RF transmitter defines two sets of RF inputs and outputs, which are first and second RF inputs and first and second and Called the second RF output. In this regard, the first RF signal is provided to the first RF input 26 and amplified by the transmitter 20. Thereafter, the amplified RF output provided by transmitter 20 is provided to first RF output 28. Similarly, the second RF signal to be amplified is applied to the second RF input of the transmitter 20 and the corresponding amplified signal is output from the second RF output 32. The first and second RF signals preferably have different frequencies.
[0016]
Referring now to FIG. 2, a perspective view of a tube structure having a common collector 38 for amplifying two RF signals is shown in accordance with one embodiment of the present invention. However, for purposes of illustration, the tube housing is not drawn so that the tube structure is more clearly visible. FIG. 2 also illustrates a power supply 24 that supplies appropriate power and modulator signals to a shared collector tube structure, as will also be described below. More particularly, the tube structure of FIG. 2 includes first and second tubes joined by a common collector. The first tube 34 includes a first anode 35 at one end and a shared collector 38 at the opposite end. Similarly, the second tube 36 includes a second anode 37 at one end and a shared collector 38 at the other end. In response to the voltage supplied by the power source, the first anode 35 and the second anode 37 are directed over the entire length of the first tube 34 and the second tube 36 and collected by the shared collector 38. Each generates an electron beam. In this regard, the collector is further preferably maintained at a voltage level predetermined by the power source to facilitate collection of the element beam. Considerable heat is generated by collecting the electron beam. Accordingly, the RF transmitter 20 preferably further includes a collector heat sink 40 that is designed to dissipate heat.
[0017]
Thus, the RF transmitter 20 of the present invention can amplify RF signals having two different frequencies within a single tube structure having a shared collector 38 and collector heat sink 40. In this regard, within the RF transmitter 20 of the present invention, electrons arrive at the shared collector 38 from opposite sides, respectively, and electrons passing through the first tube 34 arrive from one side of the collector, and the second Electrons passing through the tube 36 arrive from the other side of the collector. Thus, the RF transmitter of the present invention allows the use of a single vacuum tube element that includes a first tube portion 34 and a second tube portion 36 and a single shared collector 38. As described below in conjunction with FIG. 3, a single modulator can also modulate both the RF signals of the first and second tubes. Thus, considerable weight and bulk can be reduced compared to a conventional two-band RF transmitter having two separate tube structures with completely different elements.
[0018]
In FIG. 3, a cross-sectional view of a two-band RF transmitter 20 having a shared collector 38 according to one embodiment of the present invention is shown with a schematic representation of the power supply circuit. On each side of the shared collector 38, the RF transmitter includes first and second tubes. Each tube includes an anode 35 and an anode 37, respectively, and generates an electron beam 48 in response to an appropriate supply voltage. The first and second tubes further include delay or cavity structures 50 and 51 that extend between their respective anodes and a common collector. Thus, the electron beam 48 travels along the length of each tube, thereby passing through the cavity or delay structure before being collected by the shared collector 38.
[0019]
As is known to those skilled in the art, the electron beam serves to amplify the RF signal. In this regard, the RF signal introduced into the first tube at the first RF input 26 is amplified by the interaction of the RF signal with the electron beam 48 in the first cavity or delay structure 50. The amplified RF signal can then be extracted from the first RF output 28. Similarly, the RF signal introduced into the second tube at the second RF input 30 interacts with the electron beam generated by the second anode 37 in the second delay structure 51 and is consequently amplified. The RF signal can be extracted from the second RF output 32.
[0020]
As shown in FIG. 3 and described above, the RF transmitter 20 may further include a heater source 56, a bias voltage source 58, a collector voltage source 62, a beam voltage source 60, and a modulator 64. As is known to those skilled in the art, the heat source 56 heats the first anode 35 and the second anode 37 to facilitate the formation of an electron beam 48 in each of the two tubes. As is also known to those skilled in the art, the bias voltage source 58 and the collector voltage source 62 cooperate to provide a voltage difference between the shared collector 38 and the respective anode. Further, the beam voltage source 60 sets the voltage levels of the first delay structure 50 and the second delay structure 51, and the modulator 64 modulates each electron beam in a manner known to those skilled in the art. For modulation, the two-band RF transmitter is close to the anode and can further include a grid driven by the modulator to stop all electron beams from flowing alternately, thereby performing RF signal amplification and It is possible to alternately perform stop. In one embodiment, the modulator provides a moderate voltage and current square wave, and alternately drives the grid voltage positive and negative. The amplifier can be quickly turned on and off by modulating the electron beam with a square wave having short rise and fall times. While the RF transmitter of the present invention can include a separate heater source, bias voltage source, beam voltage source, collector voltage source and modulator for each tube, the cost and weight of the RF transmitter is shown in FIG. As shown, this is reduced by using a common element for each tube.
[0021]
Although the RF transmitter 20 of the present invention can be configured in several different ways depending on the application, an example of an RF transmitter is shown below for illustration. In this example, the RF transmitter includes a pair of RF tubes having inputs and outputs, respectively, as shown in FIG. For example, the first input can have a frequency of 30 GHz and the second input can have a frequency of 42 GHz. When the bias voltage source 58 and the collector voltage source 62 cooperatively apply a voltage of 15 to 20 KV between the collector 38 and the anodes 35, 37, respectively, and the heater source heats the anode to the appropriate temperature, each of the tube sections Generating an electron beam propagating through it. Furthermore, modulation of the electron beam is possible. In this regard, the modulator can operate the grid to cause pulse modulation of the electron beam. As a result of amplifying each of the RF signals, an RF output signal can be extracted from each of the RF outputs amplified by 10 to 45 dB. Thus, as shown in this example, the RF transmitter and associated method of the present invention allows amplification of RF signals at different frequencies while providing common elements such as a common collector and a common modulator. By using it, the overall size and weight of the RF transmitter can be reduced.
[0022]
Thus, the RF transmitter 20 according to the present invention is configured such that the collector 38 is shared between two tubes that provide output gain or amplification for RF signals that typically have two or more different frequencies. Can be done. As can be appreciated from FIG. 3, the length and weight of the RF transmitter 20 of the present invention, including a shared collector for each tube, has two completely separate tube structures, each with its own collector. Compared to conventional RF transmitters that generate two different frequencies, they can be much shorter and lighter. In addition to sharing the collector, the RF transmitter of one embodiment of the invention further includes a common modulator 64, a common heater source 56, a common bias voltage source 58, a common beam voltage source 60, a common Other elements such as collector voltage source 62 and common collector heat sink 40 can be shared. In addition, the RF transmitter can also include a single vacuum tube element that includes each tube section. Thus, as a result, the RF transmitter separately separates RF signals having two different frequencies in a small, light shared collector configuration at a lower cost than conventional designs that would require two separate tube structures. Can be amplified.
[0023]
Many modifications and other embodiments of the invention will occur to those skilled in the art who have the benefit of the teachings presented in the foregoing description and the associated figures in connection with the present invention. Accordingly, it should be understood that the invention is not limited to the specific disclosed embodiments, but that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are used herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
[Brief description of the drawings]
FIG. 1 is a perspective view of a two-band RF transmitter and associated power supply in accordance with one embodiment of the present invention.
FIG. 2 is a perspective view of a pair of tubes of an RF transmitter sharing a common collector with a shared power source, according to one embodiment of the present invention.
FIG. 3 is a cross-sectional view of a two-band RF transmitter in accordance with one advantageous embodiment of the present invention.

Claims (19)

An RF transmitter for providing a plurality of amplified radio frequency (“RF”) output signals in response to a plurality of different RF input signals, the RF transmitter comprising:
Separate electron beams with each RF tube amplifying a respective RF signal so that each RF tube has the ability to support the propagation of different RF signals, including multiple RF tubes through which multiple electron beams propagate Each RF tube section defines inputs and outputs from which RF signals are introduced and extracted, respectively , so that the transmitter can further support the propagation of
A transmitter including a common collector for collecting each of the electron beams after propagating through each of the RF tube portions, the common collector being shared by each RF tube portion.   The RF transmitter of claim 1, further comprising a modulator for modulating each of the electron beams, wherein the modulator is shared by each RF tube section.   The RF transmitter of claim 1, wherein the plurality of RF tube portions cooperate to define a common vacuum tube.   The RF transmitter of claim 3, further comprising a collector heat sink for dissipating heat generated in the common collector as the collector collects the electron beam.   The RF transmitter according to claim 3, wherein the common vacuum tube includes a klystron tube.   The RF transmitter of claim 3, wherein the common vacuum tube comprises a traveling wave tube.   The RF transmitter according to claim 1, further comprising a power source for energizing the RF tube section.   The RF transmitter of claim 1, wherein each RF tube section operates at an RF operating frequency that is different from the RF operating frequency of each of the other RF tube sections. An RF transmitter for providing a plurality of amplified radio frequency (“RF”) output signals in response to a plurality of different RF input signals,
Separate electron beams with each RF tube amplifying a respective RF signal so that each RF tube has the ability to support the propagation of different RF signals, including multiple RF tubes through which multiple electron beams propagate Each tube has an opposite end to define the input and output, and each RF tube further generates an electron beam that passes longitudinally through the tube so that it is also capable of supporting the propagation of Including an anode at one end, the transmitter further comprising:
An RF transmitter disposed proximate to each end of the RF tube section opposite the anode and including a common collector for collecting each of the electron beams after propagating through the RF tube section .   The RF transmitter of claim 9, further comprising a modulator for modulating each of the electron beams, the modulator being shared by each RF tube section.   The RF transmitter of claim 9, wherein the plurality of RF tube portions cooperate to define a common vacuum tube.   The RF transmitter of claim 11, wherein the collector further comprises a collector heat sink for dissipating heat generated in the common collector when collecting the electron beam.   The RF transmitter of claim 11, wherein the common vacuum tube comprises a klystron tube.   The RF transmitter of claim 11, wherein the common vacuum tube comprises a traveling wave tube.   The RF transmitter according to claim 9, further comprising a power source for energizing the RF tube section.   The RF transmitter of claim 9, wherein each RF tube section operates at an RF operating frequency that is different from the RF operating frequency of each of the other RF tube sections. A method of amplifying a plurality of RF signals,
Generating a plurality of electron beams propagating through each of the RF tube sections;
Introducing each of the different RF input signals into each RF tube to propagate with the separate electron beam through the RF tube;
Extracting each RF output signal from each RF tube after amplification;
Collecting the plurality of electron beams propagating through each of the RF tube sections in common using a shared collector.   The method of claim 17, further comprising modulating each of the plurality of electron beams in common.   The method of claim 17, wherein the introducing includes introducing RF signals having different frequencies into each RF tube section.

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